Plastic honeycomb core material is used extensively in aircraft structures due to its high strength and light weight. Many of the details made from this core require that the edges be chamfered. This forming is currently produced by hand held tools utilizing abrasive discs. This method is labor intensive and relies upon operator skill to produce dimensionally accurate parts. Various cutters have been tried to accomplish this contoured trimming but all the cutters tear the surface and leave a part that is ragged and heavily burred. It was found that the cutter of this invention leaves a burrless surface that does not require a subsequent abrading operation.